Feed means for staple fiber cutter



Dec. 22, 1964 H. w. HEMKER FEED MEANS FOR STAPLE FIBER CUTTER Filed Oct. 26, 1962 United States Patent 3,162,08 FEED MEANS FOR STAPLE FIBER CUTTER Herman W. Hcxnker, West Chester, P3,, assignor, by mesne assignments, to FMC Corporation, San Jose, Calif., a corporation of Delaware Filed Oct. 26, 1962, Ser. No. 233,396 6 Claims. (Cl. 33355) This invention relates to a cutter for cutting bundles or tows of continuous filaments into staple fibers or into flock length and more particularly to an improved arrangement for feeding and directing the tow into cutting position.

The type of cutter in connection with which the invention is believedto have its greatest utility involves a multibladed rotary cutting element which cooperates with an adjustably mounted stationary blade or bed knife. An example of such a cutter is shown in U.S. Patent No. 2,961,909 to Hemker et al. and the present invention constitutes an improvement over the feeding arrangement shown in said patent. With this type of cutter the tow, which will normally be quite large and may be leaving a spinning machine where it is being manufactured at a fairly constant high rate of speed, is directed into the area where the blades of the rotary element contact the stationary blade. For uniform cutting it is important that the tow be accurately positioned when it reaches the cutting area. Since the tow is being continuously supplied by the spinning machine, it is important that the cutting area be kept clear of moving parts or devices with which the tow or individual filaments of the tow may become entangled because a fouling of the tow in this area may necessitate the shutting down of the cutter for a considerable period of time.

It is an object of the present invention to provide a staple fiber cutter having improved means for feeding and directing a tow into cutting position.

It is a further object of the invention to provide a staple fiber cutter having a tow feeding arrangement which is characterized by the absence of moving parts in the vicinity of the cutting area.

Other and further objects, features and advantages of the invention will become apparent as the description of a preferred embodiment thereof proceeds.

Referring now to the drawing:

FIG. 1 is a side elevational view showing the tow feed ing arrangement of the invention; and

FIG. 2 is a perspective view of a portion of a curved chute constituting an essential element of the invention.

The cutter per se comprises a rotary drum element 10 extending from the surface of which are a plurality of blades 11 arranged at an angle to the axis of the drum. Drum 10 may be driven in any suitable manner in the direction indicated by the arrow. Blades 11 cooperate with a relatively stationary blade or bed knife 12 carried on arm 13 which may be adjusted in any suitable manner to provide the desired amount of interference between the blades 11 and 12. As shown in FIG. 1, the tow 14 is directed toward the axis of drum 10 so as to enter the cutting area at a point closely adjacent bed knife 12.

It is contemplated that the cutter will normally be used to cut a tow which is being discharged at a fairly steady rate from a spinning machine. However, while the rate of production of the tow is reasonably uniform it is not exactly so and if it is to be cut into fibers of uniform length it must be fed to the cutter at a closely controlled rate of speed and to this end speed controlled metering rolls are employed. In the present apparatus three pairs of metering rolls are used, the first pair being indicated at 15 and 16, the second pair at 17 and 18 and the third or final pair at 19 and 20. The metering rolls are rotatably mounted between a pair of vertically arranged spaced plates 21, only one of which is shown. Each of the plates 3,162,080 Patented Dec. 22, 1964 21 is provided with a flange 22 which supports the plate on the upper flange 23 of a channel member 24. Flange 22 is slotted as indicated at 25 and bolts 26 extending through the slots and through flange 23 adjustably secure plates 21 to their respective channel member 24. The channel members are mounted on a framework 27 which is preferably the same framework carrying the cutting elements but may be independent thereof.

Tow 14 is apt to contain a very large number of filaments and asit leaves the spinning machine it is more or less cylindrical in form. In order to cut the individual filaments of the tow into uniform length, it is desirable to flatten the tow into the form of a ribbon as shown in FIG. 2 before introducing it into the cutting area. To this end the upper metering rolls 15, 17 and 19 are adjustably urged toward their respective mating lower rolls. The shafts of the upper rolls are mounted in slots 27 and a pivotally mounted arm 28 carrying an adjustable weight 29 urges the shaft downward to press the roller against the tow. The tow contains a large amount of water when it leaves the spinning machine and the upper metering rolls not only flatten the tow but squeeze out excess water. It is desirable for the tow to be wet when it is cut and by adjusting the weights 2.9, the tow can be caused to leave the metering rolls with the optimum moisture 'con tent.

Lower metering rolls 18 and 20 are drivingly interconnected by suitable sprockets and a chain 34) and rolls 16 and 18 are connected by suitable sprockets and a chain 31. Roll 16 is driven through a chain and sprocket drive 32 from a variable speed drive 33.

As will be observed in FIG. 1, the metering rolls are displaced both vertically and horizontally from the cutting area or station. The tow passes through the metering rolls horizontally and as it leaves the last set of rolls it has a natural inclination to follow a certain trajectory. The metering rolls are so situated that for a particular speed of the rolls the natural trajectory of the tow would cause it to drop substantially vertically into the cutting area adjacent fixed blade 12 as shown in the drawing. The slots 25 in the bottom flanges of the metering roll supporting plates 21 permit the metering rolls to be adjusted horizontally so that for a particular desired speed of the rolls the tow can be madeto drop into substantially proper relationship with fixed blade 12.

Since one of the objects of the invention is to keep the cutting area free of moving parts, particularly rollers, the final metering rolls 19 and 20 are located at a sub stantial distance from said area. This being the case, it is not practicable to rely entirely on the natural trajectory of the tow to carry it into cutting position. For one thing, the tow is moving relatively slow at the very beginning of the operation and it would be extremely difiicult, if not impossible, to get the tow started intothe cutter, even though at full speed its trajectory would carry it there. Another reason for not relying entirely on the natural trajectory of the tow is that it may be desirable to change the speed of the tow from time to time. This would, of course, change the natural trajectory and neccessitate a repositioning of the metering rolls. It will be appreciated that the exact positioning of the metering rolls necessary to project the tow into precise cutting alignment is time consuming.

According to the present invention, a chute 34 extends from a point closely adjacent the discharge side of the final metering rolls 19 and 21 to a point closely adjacent the edge of fixed cutter blade 12. substantially conform with the natural trajectory of the tow so that for a particular speed of the tow as it leaves the metering rolls, the tow will just lightly engage the chute as it moves to the cutting area. if the speed of the tow is decreased, it will still slide along the chute and Chute 34 is curved to be carriedthereby into the cutting area. Chute 34 is 7 formed of or coated with a low friction, acid resistant material such as Teflon and may be provided with side walls 35 and 36. The chute is substantially horizontal at its upper end and is supported at that end by a bracket 37. At the lower end, the chute is substantially vertical and directed toward the axis of rotary cutting element 10. A bracket 38 supports the lower end of the chute.

A series of pairs of slotted blocks 39 are secured to the chute side walls 35 and 36 and a bar 40 having rounded ends is moutned in the slots of each pair of blocks. Secured to each bar 40 is a flap member 41 extending toward the discharge end of the chute. A clamping screw 42 is provided for each block so'that the bar 40 may be clamped to the block in position to locate the end of the flap so that the flattened tow will just pass between the end of the flap and the surface of the chute. If the tow is discharged from the final metering rolls 19 and 20 at or below the speed for which the chute is designed, flaps 41 are not needed because the trajectory of the tow will cause it to lie on the surface of the chute. However, if the speed of the metering rolls is increased, the flaps 41 prevent the tow from being projected beyond the discharge end of the chute. The lowermost flap 41 also serves an additional purpose when the tow is extra heavy, that is in the form of a fairly thick ribbon. With a thick tow, the impact of the blades 11 against the tow tends to buckle the tow before completely severing it and at high cutting speed this buckling will cause the tow to bulge away from the surface of the chute at the bottom unless the lowest fiap 41 is used. Such buckling of the tow would result in uneven movement of the tow into the cutting area and thereby cause unequal length fibers to be cut from the tow.

It will be observed that with the herein described arrangement, there are no moving parts between metering rolls 19 and 20 and the cutter. If for any reason the cutter should cease to function properly, the tow, which would continue to come from the spinning machine, will spill out of the chute and onto the floor, thereby making it an easy matter to redirect the tow to another cutter. This feature constitutes one of the major improvements over the feeding arrangement shown in the above referred to Patent No. 2,961,909 wherein a set of guiding feed rolls are located close to the cutting area. With the arrangement shown in said patent, the tow could and frequently would become Wrapped around the last set of feed rolls when the cutter did not operate properly. The results of this feed roll wrapping were sometimes disastrous.

Having thus described the invention, what is claimed 1. In a fiber cutting apparatus, a cutting station, metering rolls for projecting a tow horizontally in the direction of the cutting station, means for driving said metering rolls at a speed such as to project the tow at a predetermined linear speed, said metering rolls being located at a point displaced horizontally from and-vertically above said cutting station, and a curved chute leading from said metering rolls to said cutting station, said chute having a curvature substantially conforming to the natural trajectory of the tow when the tow is projected from the metering rolls at said predetermined linear speed, whereby the tow slides along said chute in light contact therewith.

2. The apparatus set forth in claim 1 wherein the lower end of said curved chute is substantially vertical and located in close proximity to said cutting station.

3. In a fiber cutting apparatus, a cutting station, metering rolls for projecting a tow horizontally in the direction of the cutting station, means for driving said metering rolls at a speed such as to project the tow at a predetermined linear speed, said metering rolls being located at a point displaced horizontally from the vertically above said cutting station, a curved chute leading from said metering rolls to said cutting station, said chute having \a curvature conforming to the natural trajectory of the tow when the tow is projected from the metering rolls at said predetermined speed whereby at that speed the tow slides along the chute in light contact therewith, means for increasing the speed of the metering rolls and of the tow whereby the natural trajectory of the tow is lengthened, and means for preventing the lengthened natural trajectory of the tow from carrying the tow out of contact with said chute.

4. The apparatus set forth in claim 3 wherein the last mentioned means comprises a plurality of flap members connected to said chute and extending toward the discharge end of the chute so as to confine the tow between the flap members and the chute.

-5. The apparatus set forth in Claim 3 wherein the lower end of said chute is substantially vertical and located in close proximity to said cutting station.

6. In a fiber cutting apparatus, a rotary cutting element mounted on a horizontal \axis and having a plurality of blades extending therefrom so that the blades describe a circular path as said element rotates, means for rotating said element, a bed knife engaged by the blades of said element at the top of the circular path, the line of engagement between said blades and said knife defining a cutting station, metering rolls for projecting a tow horizontally in the direction of said cutting station, means for driving said rolls at a speed which will project the tow at a preselected speed, said metering rolls being located at a point displaced horizontally from and vertically above said cutting station, and a curved chute leading from said metering rolls to said cutting station, said chute extending substantially vertically at the discharge end thereof, said chute having a curvature substantially conforming to the natural trajectory of the tow at the said preselected speed.

References Cited in the file of this patent UNITED STATES PATENTS 1,978,826 Walton Oct. 30, 1934 2,261,968 Matthews Nov. 11, 1941 2,631,668 Wicker March 17, 1953 2,683,487 Conner July 13, 1954 3,057,530 Mees Oct. 9, 1962 FOREIGN PATENTS 616,630 Canada no Mar. 21, I961 

6. IN A FIBER CUTTING APPARATUS, A ROTARY CUTTING ELEMENT MOUNTED ON A HORIZONTAL AXIS AND HAVING A PLURALITY OF BLADES EXTENDING THEREFROM SO THAT THE BLADES DESCRIBE A CIRCULAR PATH AS SAID ELEMENT ROTATES, MEANS FOR ROTATING SAID ELEMENT, A BED KNIFE ENGAGED BY THE BLADES OF SAID ELEMENT AT THE TOP OF THE CIRCULAR PATH, THE LINE OF ENGAGEMENT BETWEEN SAID BLADES AND SAID KNIFE DEFINING A CUTTING STATION, METERING ROLLS FOR PROJECTING A TOW HORIZONTALLY IN THE DIRECTION OF SAID CUTTING STATION, MEANS FOR DRIVING SAID ROLLS AT A SPEED WHICH WILL PROJECT THE TOW AT A PRESELECTED SPEED, SAID METERING ROLLS BEING 